| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| /* |
| * $Id: Variable.java 468655 2006-10-28 07:12:06Z minchau $ |
| */ |
| package org.apache.xpath.operations; |
| |
| import javax.xml.transform.TransformerException; |
| |
| import org.apache.xalan.res.XSLMessages; |
| import org.apache.xml.utils.QName; |
| import org.apache.xpath.Expression; |
| import org.apache.xpath.ExpressionOwner; |
| import org.apache.xpath.XPath; |
| import org.apache.xpath.XPathContext; |
| import org.apache.xpath.XPathVisitor; |
| import org.apache.xpath.axes.PathComponent; |
| import org.apache.xpath.axes.WalkerFactory; |
| import org.apache.xpath.objects.XNodeSet; |
| import org.apache.xpath.objects.XObject; |
| import org.apache.xpath.res.XPATHErrorResources; |
| |
| |
| /** |
| * The variable reference expression executer. |
| */ |
| public class Variable extends Expression implements PathComponent |
| { |
| static final long serialVersionUID = -4334975375609297049L; |
| /** Tell if fixupVariables was called. |
| * @serial */ |
| private boolean m_fixUpWasCalled = false; |
| |
| /** The qualified name of the variable. |
| * @serial */ |
| protected QName m_qname; |
| |
| /** |
| * The index of the variable, which is either an absolute index to a |
| * global, or, if higher than the globals area, must be adjusted by adding |
| * the offset to the current stack frame. |
| */ |
| protected int m_index; |
| |
| /** |
| * Set the index for the variable into the stack. For advanced use only. You |
| * must know what you are doing to use this. |
| * |
| * @param index a global or local index. |
| */ |
| public void setIndex(int index) |
| { |
| m_index = index; |
| } |
| |
| /** |
| * Set the index for the variable into the stack. For advanced use only. |
| * |
| * @return index a global or local index. |
| */ |
| public int getIndex() |
| { |
| return m_index; |
| } |
| |
| /** |
| * Set whether or not this is a global reference. For advanced use only. |
| * |
| * @param isGlobal true if this should be a global variable reference. |
| */ |
| public void setIsGlobal(boolean isGlobal) |
| { |
| m_isGlobal = isGlobal; |
| } |
| |
| /** |
| * Set the index for the variable into the stack. For advanced use only. |
| * |
| * @return true if this should be a global variable reference. |
| */ |
| public boolean getGlobal() |
| { |
| return m_isGlobal; |
| } |
| |
| |
| |
| |
| |
| protected boolean m_isGlobal = false; |
| |
| /** |
| * This function is used to fixup variables from QNames to stack frame |
| * indexes at stylesheet build time. |
| * @param vars List of QNames that correspond to variables. This list |
| * should be searched backwards for the first qualified name that |
| * corresponds to the variable reference qname. The position of the |
| * QName in the vector from the start of the vector will be its position |
| * in the stack frame (but variables above the globalsTop value will need |
| * to be offset to the current stack frame). |
| */ |
| public void fixupVariables(java.util.Vector vars, int globalsSize) |
| { |
| m_fixUpWasCalled = true; |
| int sz = vars.size(); |
| |
| for (int i = vars.size()-1; i >= 0; i--) |
| { |
| QName qn = (QName)vars.elementAt(i); |
| // System.out.println("qn: "+qn); |
| if(qn.equals(m_qname)) |
| { |
| |
| if(i < globalsSize) |
| { |
| m_isGlobal = true; |
| m_index = i; |
| } |
| else |
| { |
| m_index = i-globalsSize; |
| } |
| |
| return; |
| } |
| } |
| |
| java.lang.String msg = XSLMessages.createXPATHMessage(XPATHErrorResources.ER_COULD_NOT_FIND_VAR, |
| new Object[]{m_qname.toString()}); |
| |
| TransformerException te = new TransformerException(msg, this); |
| |
| throw new org.apache.xml.utils.WrappedRuntimeException(te); |
| |
| } |
| |
| |
| /** |
| * Set the qualified name of the variable. |
| * |
| * @param qname Must be a non-null reference to a qualified name. |
| */ |
| public void setQName(QName qname) |
| { |
| m_qname = qname; |
| } |
| |
| /** |
| * Get the qualified name of the variable. |
| * |
| * @return A non-null reference to a qualified name. |
| */ |
| public QName getQName() |
| { |
| return m_qname; |
| } |
| |
| /** |
| * Execute an expression in the XPath runtime context, and return the |
| * result of the expression. |
| * |
| * |
| * @param xctxt The XPath runtime context. |
| * |
| * @return The result of the expression in the form of a <code>XObject</code>. |
| * |
| * @throws javax.xml.transform.TransformerException if a runtime exception |
| * occurs. |
| */ |
| public XObject execute(XPathContext xctxt) |
| throws javax.xml.transform.TransformerException |
| { |
| return execute(xctxt, false); |
| } |
| |
| |
| /** |
| * Dereference the variable, and return the reference value. Note that lazy |
| * evaluation will occur. If a variable within scope is not found, a warning |
| * will be sent to the error listener, and an empty nodeset will be returned. |
| * |
| * |
| * @param xctxt The runtime execution context. |
| * |
| * @return The evaluated variable, or an empty nodeset if not found. |
| * |
| * @throws javax.xml.transform.TransformerException |
| */ |
| public XObject execute(XPathContext xctxt, boolean destructiveOK) throws javax.xml.transform.TransformerException |
| { |
| org.apache.xml.utils.PrefixResolver xprefixResolver = xctxt.getNamespaceContext(); |
| |
| XObject result; |
| // Is the variable fetched always the same? |
| // XObject result = xctxt.getVariable(m_qname); |
| if(m_fixUpWasCalled) |
| { |
| if(m_isGlobal) |
| result = xctxt.getVarStack().getGlobalVariable(xctxt, m_index, destructiveOK); |
| else |
| result = xctxt.getVarStack().getLocalVariable(xctxt, m_index, destructiveOK); |
| } |
| else { |
| result = xctxt.getVarStack().getVariableOrParam(xctxt,m_qname); |
| } |
| |
| if (null == result) |
| { |
| // This should now never happen... |
| warn(xctxt, XPATHErrorResources.WG_ILLEGAL_VARIABLE_REFERENCE, |
| new Object[]{ m_qname.getLocalPart() }); //"VariableReference given for variable out "+ |
| // (new RuntimeException()).printStackTrace(); |
| // error(xctxt, XPATHErrorResources.ER_COULDNOT_GET_VAR_NAMED, |
| // new Object[]{ m_qname.getLocalPart() }); //"Could not get variable named "+varName); |
| |
| result = new XNodeSet(xctxt.getDTMManager()); |
| } |
| |
| return result; |
| // } |
| // else |
| // { |
| // // Hack city... big time. This is needed to evaluate xpaths from extensions, |
| // // pending some bright light going off in my head. Some sort of callback? |
| // synchronized(this) |
| // { |
| // org.apache.xalan.templates.ElemVariable vvar= getElemVariable(); |
| // if(null != vvar) |
| // { |
| // m_index = vvar.getIndex(); |
| // m_isGlobal = vvar.getIsTopLevel(); |
| // m_fixUpWasCalled = true; |
| // return execute(xctxt); |
| // } |
| // } |
| // throw new javax.xml.transform.TransformerException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_VAR_NOT_RESOLVABLE, new Object[]{m_qname.toString()})); //"Variable not resolvable: "+m_qname); |
| // } |
| } |
| |
| /** |
| * Get the XSLT ElemVariable that this sub-expression references. In order for |
| * this to work, the SourceLocator must be the owning ElemTemplateElement. |
| * @return The dereference to the ElemVariable, or null if not found. |
| */ |
| public org.apache.xalan.templates.ElemVariable getElemVariable() |
| { |
| |
| // Get the current ElemTemplateElement, and then walk backwards in |
| // document order, searching |
| // for an xsl:param element or xsl:variable element that matches our |
| // qname. If we reach the top level, use the StylesheetRoot's composed |
| // list of top level variables and parameters. |
| |
| org.apache.xalan.templates.ElemVariable vvar = null; |
| org.apache.xpath.ExpressionNode owner = getExpressionOwner(); |
| |
| if (null != owner && owner instanceof org.apache.xalan.templates.ElemTemplateElement) |
| { |
| |
| org.apache.xalan.templates.ElemTemplateElement prev = |
| (org.apache.xalan.templates.ElemTemplateElement) owner; |
| |
| if (!(prev instanceof org.apache.xalan.templates.Stylesheet)) |
| { |
| while ( prev != null && !(prev.getParentNode() instanceof org.apache.xalan.templates.Stylesheet) ) |
| { |
| org.apache.xalan.templates.ElemTemplateElement savedprev = prev; |
| |
| while (null != (prev = prev.getPreviousSiblingElem())) |
| { |
| if(prev instanceof org.apache.xalan.templates.ElemVariable) |
| { |
| vvar = (org.apache.xalan.templates.ElemVariable) prev; |
| |
| if (vvar.getName().equals(m_qname)) |
| { |
| return vvar; |
| } |
| vvar = null; |
| } |
| } |
| prev = savedprev.getParentElem(); |
| } |
| } |
| if (prev != null) |
| vvar = prev.getStylesheetRoot().getVariableOrParamComposed(m_qname); |
| } |
| return vvar; |
| |
| } |
| |
| /** |
| * Tell if this expression returns a stable number that will not change during |
| * iterations within the expression. This is used to determine if a proximity |
| * position predicate can indicate that no more searching has to occur. |
| * |
| * |
| * @return true if the expression represents a stable number. |
| */ |
| public boolean isStableNumber() |
| { |
| return true; |
| } |
| |
| /** |
| * Get the analysis bits for this walker, as defined in the WalkerFactory. |
| * @return One of WalkerFactory#BIT_DESCENDANT, etc. |
| */ |
| public int getAnalysisBits() |
| { |
| org.apache.xalan.templates.ElemVariable vvar = getElemVariable(); |
| if(null != vvar) |
| { |
| XPath xpath = vvar.getSelect(); |
| if(null != xpath) |
| { |
| Expression expr = xpath.getExpression(); |
| if(null != expr && expr instanceof PathComponent) |
| { |
| return ((PathComponent)expr).getAnalysisBits(); |
| } |
| } |
| } |
| return WalkerFactory.BIT_FILTER; |
| } |
| |
| |
| /** |
| * @see org.apache.xpath.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor) |
| */ |
| public void callVisitors(ExpressionOwner owner, XPathVisitor visitor) |
| { |
| visitor.visitVariableRef(owner, this); |
| } |
| /** |
| * @see Expression#deepEquals(Expression) |
| */ |
| public boolean deepEquals(Expression expr) |
| { |
| if(!isSameClass(expr)) |
| return false; |
| |
| if(!m_qname.equals(((Variable)expr).m_qname)) |
| return false; |
| |
| // We have to make sure that the qname really references |
| // the same variable element. |
| if(getElemVariable() != ((Variable)expr).getElemVariable()) |
| return false; |
| |
| return true; |
| } |
| |
| static final java.lang.String PSUEDOVARNAMESPACE = "http://xml.apache.org/xalan/psuedovar"; |
| |
| /** |
| * Tell if this is a psuedo variable reference, declared by Xalan instead |
| * of by the user. |
| */ |
| public boolean isPsuedoVarRef() |
| { |
| java.lang.String ns = m_qname.getNamespaceURI(); |
| if((null != ns) && ns.equals(PSUEDOVARNAMESPACE)) |
| { |
| if(m_qname.getLocalName().startsWith("#")) |
| return true; |
| } |
| return false; |
| } |
| |
| |
| } |
